The use of abdominal field blocks is well known for relieving pain experienced by patients after abdominal surgery. Conventional blocks, however, provide limited analgesic fields and, thus, multiple blind injections were usually required, with the success of such injections being unpredictable.
Transversus abdominis plane (TAP) blocks are a fairly recently developed single entry point procedure that accesses a number of the abdominal wall nerves, thereby providing a more widespread analgesic effect. The goal of a TAP block is to deposit local anesthetic in the plane between the internal oblique and transversus abdominis muscles to target the spinal nerves in this plane. The block is typically preformed blind, with the point of entry for the blind tap being the patient's triangle of Petit situated between the lower costal margin and the iliac crest and bound anteriorly by the external oblique muscle and posteriorly by the latissimus dorsi. The blind technique relies on the practitioner feeling double “pops” as the needle traverses the external oblique and internal oblique muscles.
Ultrasound-guided TAP blocks are gaining acceptance for providing better localization and injection of the local anesthetic with improved accuracy. With the ultrasound procedure, an ultrasound probe is placed in a plane essentially transverse to the lateral abdominal wall between the lower costal margin and the iliac crest. Ultrasonic imaging allows for a more accurate deposition of the local anesthetic in the correct neurovascular plane. Ultrasound-guided TAPS are indicated for essentially any lower abdominal surgery, including appendectomy, hernia repair, caesarean section, abdominal hysterectomy, and prostatectomy. Effectiveness has also been shown in laparoscopic surgery.
The present invention provides further advancements in the methodology and devices for ultrasound TAP procedures.